Apple is, of course, locked in an in-going war with Google's mobile operating system (OS) for control of the smartphone market. Apple is increasingly targeting Android users to get them to switch (it also just launched an app to make it easier to do so), and it rarely releases any of its apps and services on the platform.

But this time around, Apple has decided it is worth launching a product in Android's ecosystem. The release of Apple Music is brought about by necessity: Apple dominated the music industry for a long times via iTunes, but paid downloads are now in decline. Streaming is the hot new way to consume music, and rival Spotify has an estimated 86% of that market.

Apple needed to release Apple Music if didn't want to get left behind, and it needs to reach the maximum number of people as fast as possible in order to counter the advantage established players like Spotify already have. And that means launching on Android.

It's reminiscent of how despite then-CEO Steve Jobs' initial adamant refusals, Apple ultimately released iTunes for Windows in 2003 to ensure the product could reach the maximum number of potential users. And the same has now happened again, with Apple Music also available on Windows.